I've used a few of the hall effect current sensors from Pololu for this type of thing also. In a project on a boat I measured solar and generator input as well as total battery discharge using 3 of these modules. I also use them in my benchtop power supply. This +/- 5A one based on Allegro ACS714 will give you the best resolution for the range you're measuring.

Cheers ! Geoff

"There is no problem so bad you can't make it worse"- retired astronaut Chris Hadfield

Unfortunately neither of those projects will be too useful to you I think. The bench supply uses an ATX PSU with power broken out to 3v3, 5, 12 and variable posts on the enclosure. A 20x4 character display outputs the current drawn from each... Plus temperature and a clock since it was already over the top.

The power hub on the boat is really a fuse box and power distribution board with a screen. The solar and outboard power are routed through it before the battery and all battery output goes through it also. This gives a simple indication of total charge or discharge of the battery since reset, instantaneous and cumulative moving average for those statistics... And cabin temperature, because I had extra pins

Geoff

"There is no problem so bad you can't make it worse"- retired astronaut Chris Hadfield

Put a small value, precision shunt resistor in series with the cell and measure the voltage drop across it.

In solar battery charging systems every bit of energy is precious. A current shunt is just throwing away energy. Granted that it is a small amount but, if it can be avoided it should be. The use of a Hall sensor would be my first choice. Search ebay and you will find Hall sensors ranging from 5A to 30A .

Put a small value, precision shunt resistor in series with the cell and measure the voltage drop across it.

In solar battery charging systems every bit of energy is precious. A current shunt is just throwing away energy. Granted that it is a small amount but, if it can be avoided it should be. The use of a Hall sensor would be my first choice. Search ebay and you will find Hall sensors ranging from 5A to 30A .

True, but the first couple of Hall sensors that I checked out used 50mW while operating so you'd have to be careful.